Joe Asakura, known as G-2 or Joe the Condor, is a central figure in Gatchaman II, but his role is defined by the events that preceded it. The character is introduced in the original Gatchaman series as the Science Ninja Team's second-in-command, a weapons expert and marksman driven by a deep-seated thirst for vengeance against the terrorist organization Galactor. Born George Asakura, he witnessed the assassination of his parents, Giuseppe and Katarina, by a Galactor agent when he was eight years old. He was rescued by Dr. Kozaburo Nambu, who falsified his death and raised him under a new identity, secretly training him as a member of the Science Ninja Team alongside other wards, including Ken Washio, the team's leader. Joe's defining traits in the original series are his impulsiveness, aggression, and a preference for direct confrontation, often clashing with Ken over strategy. Despite his cynical, lone-wolf exterior, he shares a deep and unspoken bond with his teammates. At the end of the first series, Joe seemingly died after a sacrificial final battle against Galactor, though his body was never recovered.

The sequel series Gatchaman II begins two years after this apparent death. The Science Ninja Team is called back into action when Galactor resurfaces under the leadership of the alien entity known as Leader X. Early in the new series, the team is aided by a mysterious figure who operates from the shadows, and it is eventually revealed that this is Joe, having survived his near-fatal injuries. The explanation for his survival is a fundamental change to his character. Joe was rescued at the brink of death by a remorseful ex-Galactor scientist named Dr. Rafael, who rebuilt him using advanced cybernetics. This transformation turns Joe into a cyborg, granting him extraordinary durability and making him nearly indestructible. His new body can withstand extreme pressure, intense heat and cold, and emerge from massive explosions with only minor scrapes. This physical change deeply impacts his personality and motivations. While his impulsive nature and dedication to destroying Galactor remain, they are now filtered through his new existence as a machine. Joe begins to view himself as a living weapon whose only purpose is combat, which leads him to act recklessly and throw himself into the most dangerous situations without regard for his own safety, often as a way to protect his teammates.

The discovery of his cybernetic nature becomes a significant plot point. He attempts to keep it a secret, but when it is revealed, it deepens his internal conflict as he struggles with his remaining humanity. For instance, it is noted that as a cyborg, Joe does not sweat, but he is still capable of crying, a small but powerful indicator of the man inside the machine. His body also requires recharging after expending large amounts of energy, leaving him vulnerable at times, and he can be affected by strong electromagnetic fields. A crucial weakness is implanted in him: a bomb is placed near his heart, linked to his new body. This bomb serves as a failsafe, preventing him from directly destroying Leader X himself, as the act would also kill Joe. His key relationships are also colored by his new state. His reunion with Ken is initially marked by Ken's anger over Joe's faked death, but the deep friendship and rivalry between the two persists. Dr. Nambu, still carrying guilt over the secrets he kept regarding Joe's parents, continues to support him. Throughout Gatchaman II, Joe struggles with the reality of being a cyborg, the implanted bomb that limits his actions, and his desire for a normal life, even as he uses his enhanced abilities to relentlessly pursue Galactor and fulfill his mission to safeguard his comrades.